Apparatus, Systems And Methods For Cross Track Error Calculation From Active Sensors

ABSTRACT

The disclosed apparatus, systems and methods relate to determining cross track error between a stored planted location and the actual physical location of plants. An array of active light sensors is mounted on a vehicle for travel above the plants. The array of active light sensors generate an electrical signal from each sensor corresponding to the reflected light from the sensor. A computer system generates a reflectance curve from the array of sensors to determine the location of a plant below the array of sensors and also generates the cross track error.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.14/823,525, filed Aug. 11, 2015, which claims priority to U.S.Provisional Application No. 62/035,590, filed Aug. 11, 2014, both ofwhich are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The disclosed technology relates generally to devices, systems andmethods for system for determining cross track error and in particular,to the devices, methods, and design principles allowing the use ofsensing systems, such as light and mechanical sensing systems, tocompare the actual location of plants with stored locations of plant.This has implications in many agricultural industries.

BACKGROUND

The disclosure relates to apparatus, systems and methods for determiningcross track error.

Current guidance systems assume that guidance lines created with GPS area true reflection of the actual planting lines. Reducing error from GPSdrift by adding options such as Real-time kinematic (RTK) correctionwill help create a very repeatable guidance line, but does not take intoaccount the small errors that occur during the planting or applicationprocess. If there is an accidental shift during planting, the guidanceline will indicate the rows were planted straight, but the plants willemerge shifted.

Additionally, GPS units may track slightly differently between GPS unitscreating a slightly different guidance line placement between planterand application equipment. Each of these instances of variation from thecalculated guidance line would be corrected by a sensor controlledguidance line which responds to the plant location rather than assumeplanted location.

Many sidedress applicators know of these issues and choose to manuallyguide the equipment through the field rather than let an error in GPSguidance destroy a large section of their plants. The problem with thisis human error can also cause incidental drift which will also lead todamage of plants.

U.S. Pat. No. 5,585,626 divulges the idea of using light sensors forguidance assistance, but does not provide any details on how todetermine actual row location.

Current systems calculate cross track error based on where it is assumedthe rows will be at. Using light sensors, the cross track error will becreated from accurate measurements of the physical location of the plantrow.

BRIEF SUMMARY

Discussed herein are various devices, systems and methods relating to anarray of active light sensors mounted on an agricultural vehicle and anassociated computer system for detecting the actual location of plantsin a row and computing the difference between the actual row locationfrom the location generated during planting using a GPS system. Thearray of active light sensors and associated computer system determinesthe location of a plant in a row by identifying a peak reflectance valuewhich corresponds to the center of the plant. The sensors and associatedcomputer system are able to distinguish desired crop plants from foreignvegetation, such as weeds, and to disregard sensor readings from theforeign vegetation. The sensors and associated computer system are ableto distinguish between soil and vegetation readings and disregard soilreadings so as to identify rows of plants and to disregard sensorreadings of temporary abrupt changes in vegetation location that arecaused by unintended seed placement or errant plant growth.

The sensors and associated computer system are, in certain Examples,interconnected with an automatic steering system to steer anagricultural vehicle along the path of the actual row of plants or to aparallel GPS manual guidance system to assist in guiding the operatoralong the path of the actual row of plants.

In another Example, the sensors and associated computer system can moreaccurately detect the path of the plants compared to the direction oftravel of the vehicle by using at least two sensor arrays over the samerows. The system would be able to more quickly respond to changes inpath direction by calculating the difference in location between a frontmounted and rear mounted array. The system could then predict the pathdirection very near to the current location of the vehicle, which isespecially useful for detecting when rows of plants start to curve.

In another Example, the sensors and associated computer system use anarray of active light sensors mounted on a vehicle to determine thelateral position of vegetation relative to a ground engaging member ofthe vehicle and determines a crow-track driving error.

While multiple embodiments are disclosed, still other embodiments of thedisclosure will become apparent to those skilled in the art from thefollowing detailed description, which shows and describes illustrativeembodiments of the disclosed apparatus, systems and methods. As will berealized, the disclosed apparatus, systems and methods are capable ofmodifications in various obvious aspects, all without departing from thespirit and scope of the disclosure. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an array of sensors scanning a singleplant to create a reflectance curve, according to one implementation.

FIG. 2 is a schematic diagram of an array of sensors used to find thegap between rows by comparing reflectance curves, according to oneimplementation.

FIG. 3 is a further schematic diagram of the implementation of FIG. 1,showing a block diagram of the vehicle control systems.

FIG. 4 is a further schematic diagram of the implementation of FIG. 2,showing a block diagram of the vehicle control systems.

DETAILED DESCRIPTION

As shown in the implementations of the calculation device, method andsystem 10 shown in FIGS. 1 and 3, an array 12 of active light sensors 16is passed over a growing plant 16. Each sensor in the array 12 measuresa reflectance value when it is over a part of the plant 16. Thereflectance values are compiled to form a reflectance curve of the plantbiomass. This reflectance curve is used in a variety of ways todetermine cross track error from accurate measurements of the physicallocation of the plant row and to assist in guidance of an agriculturalvehicle on which the array is mounted as it passes through a field ofcrops.

In the implementation of the calculation device, method and system 10shown in FIGS. 2 and 4, there is illustrated apparatus comprising anarray 12 of sensors 14 that are used to find the gap between rows. If acrop type has little to no peak reflectance value at the center of theplant, sensors 14 can be used to indicate the total area of two plants.Knowing the gap between rows based on planter spacing, the system cancalculate the center of the gap between rows to create a cross trackerror from.

In these and other implementations, the vehicle 20 has a computer system22 configured to calculate a cross track driving error by determiningthe lateral relative position of vegetation as measured by the sensorsto a ground engaging member of the vehicle 20. The computer system 22includes a storage device 24, module or other device configured to storea Zero Error Position on the sensor array 12 that defines the vehicle istraveling the desired path whenever vegetation is passing under ZeroError Position. The computer system 22 also is used to determine thedirection of cross track vehicle driving error by comparing the positionon the active light sensor array 12 that vegetation is passing under tothe Zero Error Position is used to determine the magnitude of crosstrack vehicle driving error by comparing the position on the activelight sensor array that vegetation is passing under to the Zero ErrorPosition, for example by adding the spacing between light sensors onsaid sensor array from where vegetation is passing under array to theZero Error Position. In an exemplary embodiment, a display 26 is used toshow an operator of the vehicle 20 the direction and magnitude of crosstrack vehicle driving error.

In another embodiment, the computer system 22 is interconnected with anautomatic steering system 28 and uses the direction and magnitude ofcross track vehicle driving error to automatically steer vehicle down adesired path. In this embodiment, a further refinement automaticallydetermines when the cross track driving error from the active lightsensor array 12 is sufficiently accurate to automatically engagesteering.

In another embodiment, the computer system 22 accepts and uses a manualinput to compensate direction and magnitude of cross track vehicledriving error for changes in vegetation biomass. For example, the manualinput can be a user entered vegetation biomass parameter (e.g. growthstage, plant height).

In another embodiment, the computer system 22 automatically compensatesthe direction and magnitude of cross track vehicle driving error forchanges in vegetation biomass using an algorithm that compensates forchanging biomass by interpreting sensor signals without any user enteredvegetation biomass parameters except for crop type.

A particular application of the disclosed implementations is detectingcross track driving error with the active light sensor array mounted toa vehicle used to detect the middle of a row space between adjacentrows; that is, using the array to identify adjacent rows of plants andcalculating the line of halfway points. In another application of thedisclosed implementations, the active light sensor array mounted on avehicle is used to augment the cross track driving error of a parallelGPS manual guidance or automatic steering system, and may includecomparing active light sensor readings to a GPS readings of a parallelguidance line system and/or comparing active light sensor readings ofone row of crop to another row of crop sensed by the active light sensorarray.

In another embodiment, the active light sensor readings from vegetationare compared to a mechanical row feeler system 30.

The disclosed implementations can be used to determine a cross trackdriving error by using the active light sensor array system to detectthe location plants and compare it to the stored row spacing as planted,as well as verifying the location of two or more rows or one or more rowspaces by comparing detected row space to actual planted row spacing.

The disclosed implementations can also be used to detect cross trackdriving error with the active light sensor array mounted on a vehicle bycomputing a rolling average of sensor readings in the direction oftravel or, alternatively, computing an average from two or more sensorslaterally positioned relative to the direction of travel.

The disclosed implementations can also be used to detect cross trackdriving error with an active light sensor array where system compensatesfor one or more wind parameters, such as wind speed and wind direction.In one such embodiment, the wind parameter is measured in real time onthe vehicle 20 via a detection system 32 and wherein an algorithm usesthe combination of wind parameters and sensor data to detect a rowoffset distance correction for cross track driving error.

The disclosed implementations can also be used to detect GPS drift basedon plant row location compared to GPS created guidance line location.The invention shifts the GPS created guidance lines to the correctedlocation based on the location of the vehicle relative to the crop rows.In a preferred embodiment, an algorithm calculates a temporarycorrection for the guidance from a GPS created guidance line based onthe sensor array detection of shifts in the plant rows.

The disclosed implementations can also be used to more accurately detectthe path of the plants compared to the direction of travel of thevehicle by using at least two sensor arrays 12A, 12B over the same rows,as is shown in FIGS. 3-4. In this arrangement, the system 10 is able tomore quickly respond to changes in path direction by calculating thedifference in location between a front mounted and rear mounted array.The system 10 is thereby able to predict the path direction very near tothe current location of the vehicle, which is especially useful fordetecting when row of plants start to curve.

The disclosed implementations can also be used to correct cross trackdriving error for vegetation on slopes that do not grow perpendicular tosoil surface by using slope readings from a real time slope sensor onthe vehicle.

In various implementations, the cross track driving error of a mountedor drawn implement is determined for the purpose of either passively oractively steering the implement equipment.

The sensors preferably have a narrow and defined viewing area todetermine an accurate amount of biomass directly in the viewing area ofthe sensor. The sensors also preferably sample data at a very high rate,even more preferably above 100 Hz.

The foregoing description and drawings comprise illustrative embodimentsof the disclosed implementations. The foregoing embodiments and themethods described herein may vary based on the ability, experience, andpreference of those skilled in the art. Merely listing the steps of themethod in a certain order does not constitute any limitation on theorder of the steps of the method. The foregoing description and drawingsmerely explain and illustrate the invention, and the invention is notlimited thereto, except insofar as the claims are so limited. Thoseskilled in the art who have the disclosure before them will be able tomake modifications and variations therein without departing from thescope of the invention.

Although the disclosure has been described with reference to preferredembodiments, persons skilled in the art will recognize that changes maybe made in form and detail without departing from the spirit and scopeof the disclosed apparatus, systems and methods.

What is claimed is:
 1. A system for determining cross track error,comprising: a. at least one active light sensor array suspended on avehicle; and b. a computer system comprising a processor in operationalcommunication with the at least one active light sensor array, whereinthe processor is configured to: i. establish an actual plant positionfrom the at least one active light sensor array, and ii. compare theactual plant position with a stored plant position to determinecross-track error.
 2. The system of claim 1, wherein the processor isfurther configured to: a. generate a reflectance curve, and b. establishthe actual plant position from the reflectance curve.
 3. The system ofclaim 1, wherein the computer system comprises a storage deviceconfigured to store a zero error position on the sensor array.
 4. Thesystem of claim 1, wherein the zero position error defines a desiredvehicle path.
 5. The system of claim 4, wherein the vehicle comprises anautomatic steering system operationally integrated with the computersystem and configured to receive the desired vehicle path.
 6. The systemof claim 1, wherein the processor is configured to establish a directionof cross-track driving error.
 7. The system of claim 1, wherein theprocessor is configured to establish a magnitude of cross-track vehicledriving error.
 8. The system of claim 1, further comprising aground-engaging member, wherein the processor is configured to calculatea cross-track driving error by determining a lateral relative positionof vegetation.
 9. A cross-track error detection device for a vehicle,comprising: a. at least one actual plant position sensor; and b. acomputer system comprising a processor and memory, wherein: i. thememory is configured to store a stored plant position, ii. the at leastone actual plant position sensor is configured to establish an actualplant position, and iii. the computer system is operationally integratedwith the at least one actual plant position sensor and configured todetermine cross-track error by comparing the actual plant position tothe stored plant position.
 10. The cross-track error detection device ofclaim 9, wherein the at least one actual plant position sensor comprisesat least one light sensor and at least one mechanical sensor.
 11. Thecross-track error detection device of claim 9, wherein the computersystem is operationally integrated with an automatic steering system.12. The cross-track error detection device of claim 11, wherein thecomputer system is configured to establish: a. a direction ofcross-track driving error; b. a magnitude of cross-track vehicle drivingerror; and c. a zero error position.
 13. The cross-track error detectiondevice of claim 11, wherein the computer system is configured toestablish a zero position error and a desired vehicle path for theautomatic steering system.
 14. The cross-track error detection device ofclaim 11, wherein the vehicle comprises an automatic steering systemoperationally integrated with the computer system and configured toreceive a desired vehicle path.
 15. A cross-track error detection devicefor a vehicle with an automatic steering system, comprising: a. at leastone light sensor; b. at least one mechanical sensor; and c. a computersystem comprising a processor and memory, wherein: i. the memory isconfigured to store a stored plant position, ii. the processor isconfigured to establish an actual plant position from the at least onelight sensor or the at least one mechanical sensor, and iii. thecomputer system is configured to determine cross-track error bycomparing the actual plant position to the stored plant position andoperationally integrated with the automatic steering system.
 16. Thecross-track error detection device of claim 15, wherein the computersystem is configured to generate a reflectance curve from the at leastone light sensor.
 17. The cross-track error detection device of claim15, wherein the computer system is configured to establish a zero errorposition.
 18. The cross-track error detection device of claim 17,wherein the computer system executes an algorithm configured tocompensate for changing biomass by interpreting signals from the atleast one light sensor and the at least one mechanical sensor.
 19. Thecross-track error detection device of claim 15, wherein the at least onelight sensor is an active light sensor array.
 20. The cross-track errordetection device of claim 15, wherein the computer system is configuredto accept and use a manual input to compensate direction and magnitudeof cross track vehicle driving error.